Create FAQs for history archive to remote file + to download

Removed the incomplete/outdated instructions from https://training.galaxyproject.org/training-material/faqs/galaxy/histories_transfer_entire_histories_from_one_galaxy_server_to_another.html

At next release (24.N), once process stabilized, expanded, and available at more public servers: write up the instructions for each separately as two new FAQs, name them all in a similar way, give each a header with the 3 options, and cross link.